<template>
  <el-select ref="el-tree-select" :value="valueTitle" :placeholder="placeholder" :clearable="clearable" filterable :filter-method="filterMethod" :disabled="disabled" :size="size ? size : 'mini'" @clear="clearHandle" @node-click="handleNodeClick" @visible-change="visibleChange($event)">
    <el-option :value="valueTitle" :label="valueTitle" :disabled="valueTitle === selfId">
      <el-tree id="tree-option" ref="selectTree" :accordion="accordion" :expand-on-click-node="false" :data="options" :props="props" :node-key="props.value" default-expand-all :filter-node-method="filterNode" @node-click="handleNodeClick" />
    </el-option>
  </el-select>
</template>
<script>
export default {
  name: 'ElTreeSelect',
  props: {
    /* 配置项 */
    props: {
      type: Object,
      default: () => {
        return {
          value: 'id', // ID字段名
          label: 'title', // 显示名称
          children: 'children' // 子级字段名
        }
      }
    },
    size: {
      type: String,
      default: () => {
        return ''
      }
    },
    /* 选项列表数据(树形结构的对象数组) */
    options: {
      type: Array,
      default: () => {
        return []
      }
    },
    /* 初始值 */
    value: {
      type: String,
      default: () => {
        return null
      }
    },
    /* 可清空选项 */
    clearable: {
      type: Boolean,
      default: () => {
        return true
      }
    },
    /** 是否禁用 */
    disabled: {
      type: Boolean,
      default: () => {
        return true
      }
    },
    /* 自动收起 */
    accordion: {
      type: Boolean,
      default: () => {
        return true
      }
    },
    selfId: {
      type: String,
      default: () => {
        return ''
      }
    },
    searchKey: {
      type: String,
      default: () => {
        return ''
      }
    },
    placeholder: {
      type: String,
      default: () => {
        return '请选择'
      }
    }
  },
  data() {
    return {
      valueId: this.value, // 初始值
      valueTitle: '',
      defaultExpandedKey: []
    }
  },
  watch: {
    value(val) {
      this.valueId = this.value
      this.initHandle()
    }
  },
  mounted() {
    this.initHandle()
  },
  methods: {
    // 初始化值
    initHandle() {
      /* 编辑关闭新增 还是出现编辑时显示的字段所以加了else */
      if (this.valueId) {
        this.valueTitle = this.$refs.selectTree.getNode(this.valueId).data[
          this.props.label
        ] // 初始化显示
        this.$refs.selectTree.setCurrentKey(this.valueId) // 设置默认选中
        this.defaultExpandedKey = [this.valueId] // 设置默认展开
      } else {
        this.valueTitle = ''
      }
      this.$nextTick(() => {
        const scrollWrap = document.querySelectorAll(
          '.el-scrollbar .el-select-dropdown__wrap'
        )[0]
        const scrollBar = document.querySelectorAll(
          '.el-scrollbar .el-scrollbar__bar'
        )
        scrollWrap.style.cssText =
          'margin: 0px; max-height: none; overflow: hidden;'
        scrollBar.forEach((ele) => (ele.style.width = 0))
      })
    },
    // 切换选项
    handleNodeClick(node) {
      this.$refs['el-tree-select'].blur()
      this.valueTitle = node[this.props.label]
      this.valueId = node[this.props.value]
      this.$emit('getValue', this.valueId, node)
      this.$emit('getNode', node)
      this.defaultExpandedKey = []
      this.$refs['selectTree'].filter()
    },
    // 清除选中
    clearHandle() {
      this.valueTitle = ''
      this.valueId = null
      this.defaultExpandedKey = []
      this.clearSelected()
      this.$emit('getValue', null)
      this.$emit('getNode', null)
      // 清空还原源数据
      this.$refs['selectTree'].filter()
    },
    /* 清空选中样式 */
    clearSelected() {
      const allNode = document.querySelectorAll('#tree-option .el-tree-node')
      allNode.forEach((element) => element.classList.remove('is-current'))
    },
    /** 遍历查询 */
    filterNode(value, data) {
      if (!value) return true
      if (data[this.searchKey]) {
        return data[this.searchKey].indexOf(value) !== -1
      }
    },
    filterMethod(query) {
      // 调用树形控件的过滤
      this.$refs['selectTree'].filter(query)
      // 忽略选择器本身的过滤
      return true
    },
    /* 树结构搜索了不存在的时候下拉收回再打开就一个值都没了（然后加了下拉框出现/隐藏时触发2022-06-29 yqy） */
    visibleChange($event) {
      if ($event === false) {
        this.$refs['selectTree'].filter()
      }
    }
  }
}
</script>
<style scoped >
.el-scrollbar .el-scrollbar__view .el-select-dropdown__item {
  height: auto;
  max-height: 250px;
  padding: 0;
  overflow: hidden;
  overflow-y: auto;
}
.el-select-dropdown__item.selected {
  font-weight: normal;
}
ul li >>> .el-tree .el-tree-node__content {
  height: auto;
  padding: 0 20px;
}
.el-tree-node__label {
  font-weight: normal;
}
.el-tree >>> .is-current .el-tree-node__label {
  color: #409eff;
  font-weight: 700;
}
.el-tree >>> .is-current .el-tree-node__children .el-tree-node__label {
  color: #606266;
  font-weight: normal;
}
</style>
